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[texts]String Theory - J. L. F. Barbon
This is a rendering of a review talk on the state of String Theory, given at the EPS-2003 Conference, intended for a wide audience of experimental and theoretical physicists. It emphasizes general ideas rather than technical aspects.
Downloads: 42 4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars(1 review)
[texts]Causal set as a discretized phase spacetime - Roman Sverdlov
The first goal of this paper is to show that discreteness, locality, and relativistic covariance can peacefully coexist if the ordinary spacetime (OST) is replaced with phase spacetime (PST) as a geometric background of a Poisson process, where PST is a spacetime generalization of a notion of phase space (this is a 7-dimensional version of the 8-dimensional structure proposed by Caianiello). Furthermore, Caianiello's idea of finite acceleration is implemented...
Downloads: 19 4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars(1 review)
[texts]Chronon corrections to the Dirac equation - Andrei A. Galiautdinov
The Dirac equation is not semisimple. We therefore regard it as a contraction of a simpler decontracted theory. The decontracted theory is necessarily purely algebraic and non-local. In one simple model the algebra is a Clifford algebra with 6N generators. The quantum imaginary $\hbar i$ is the contraction of a dynamical variable whose back-reaction provides the Dirac mass. The simplified Dirac equation is exactly Lorentz invariant but its symmetry group is SO(3,3), a decontraction of the Poinca...
Downloads: 17 5.00 out of 5 stars5.00 out of 5 stars5.00 out of 5 stars5.00 out of 5 stars5.00 out of 5 stars(1 review)
[texts]Numeration systems on a regular language - Pierre B. A. Lecomte
Generalizations of linear numeration systems in which the set of natural numbers is recognizable by finite automata are obtained by describing an arbitrary infinite regular language following the lexicographic ordering. For these systems of numeration, we show that ultimately periodic sets are recognizable. We also study the translation and the multiplication by constants as well as the order dependence of the recognizability.
Downloads: 1
[texts]Conjugacy of Coxeter elements - Henrik Eriksson
For a Coxeter group (W,S), a permutation of the set S is called a Coxeter word and the group element represented by the product is called a Coxeter element. Moving the first letter to the end of the word is called a rotation and two Coxeter elements are rotation equivalent if their words can be transformed into each other through a sequence of rotations and legal commutations. We prove that Coxeter elements are conjugate if and only if they are rotation equivalent...
Downloads: 2
[texts]On the dimerized phase in the cross-coupled antiferromagnetic spin ladder - G. Barcza
We revisit the phase diagram of the frustrated s=1/2 spin ladder with antiferromagnetic rung and diagonal couplings. In particular, we reexamine the evidence for the columnar dimer phase, which has been predicted from analytic treatment of the model and has been claimed to be found in numerical calculations. By considering longer chains and by keeping more states than in previous work using the density-matrix renormalization group, we show that the numerical evidence presented previously for the...
Downloads: 4
[texts]Financial bubbles analysis with a cross-sectional estimator - Frederic Abergel
We highlight a very simple statistical tool for the analysis of financial bubbles, which has already been studied in [1]. We provide extensive empirical tests of this statistical tool and investigate analytically its link with stocks correlation structure.
Downloads: 4
[texts]A dependent nominal type theory - James Cheney
Nominal abstract syntax is an approach to representing names and binding pioneered by Gabbay and Pitts. So far nominal techniques have mostly been studied using classical logic or model theory, not type theory. Nominal extensions to simple, dependent and ML-like polymorphic languages have been studied, but decidability and normalization results have only been established for simple nominal type theories...
[texts]Left cells in type $B_n$ with unequal parameters - C. Bonnafe
Kazhdan and Lusztig have shown that the partition of the symmetric group of degree $n$ into left cells is given by the Robinson-Schensted correspondence. The aim of this paper is to provide a similar description of the left cells in type $B_n$ for a special class of choices of unequal parameters. This is based on a generalization of the Robinson-Schensted correspondence for type $B_n$. We also give an explicit description of the left cell representations and show that they are irreducible and co...
Downloads: 1
[texts]arxiv-0907.4465
[texts]Correlation between lasing and transport properties in a quantum dot-resonator system - Pei-Qing Jin
We study a double quantum dot system coherently coupled to an electromagnetic resonator. By suitably biasing the system, a population inversion can be created between the dot levels. The resulting lasing state exists within a narrow resonance window, where the transport current correlates with the lasing state. It allows probing the lasing state via a current measurement. Moreover, the resulting narrow current peak opens perspective for applications of the setup for high resolution measurements.
Downloads: 3
[texts]Microwave-induced flow of vortices in long Josephson junctions - F. L. Barkov
We report experimental and numerical study of microwave-induced flow of vortices in long Josephson junctions at zero dc magnetic field. Our intriguing observation is that applying an ac-bias of a small frequency $f \ll f_p $ and sufficiently large amplitude changes the current-voltage characteristics ($I$-$V$ curve) of the junction in a way similar to the effect of dc magnetic field, well known as the flux-flow behavior...
Downloads: 2
[texts]Non-Critical Pure Spinor Superstrings - Ido Adam
We construct non-critical pure spinor superstrings in two, four and six dimensions. We find explicitly the map between the RNS variables and the pure spinor ones in the linear dilaton background. The RNS variables map onto a patch of the pure spinor space and the holomorphic top form on the pure spinor space is an essential ingredient of the mapping. A basic feature of the map is the requirement of doubling the superspace, which we analyze in detail...
[texts]Effect of earth rotation on pair production of Standard Model Higgs bosons at linear colliders in the noncommutative space-time - Prasanta Kumar Das
We study the neutral Higgs boson pair production through $e^{+} e^{-}$ collision in the noncommutative(NC) extension of the standard model using the Seiberg-Witten maps of this to the first order of the noncommutative parameter $\Theta_{\mu \nu}$. This process is forbidden in the standard model at the tree level with background space-time being commutative. After including the effects of earth's rotation we analyse the time-averaged cross section of the pair production of Higgs boson (in the lig...
Downloads: 3
[texts]Dissipation and Vortex Creation in Bose-Einstein Condensed Gases - B. Jackson
We solve the Gross-Pitaevskii equation to study energy transfer from an oscillating `object' to a trapped Bose-Einstein condensate. Two regimes are found: for object velocities below a critical value, energy is transferred by excitation of phonons at the motion extrema; while above the critical velocity, energy transfer is via vortex formation. The second regime corresponds to significantly enhanced heating, in agreement with a recent experiment.
[texts]On the Local Well-posedness of a 3D Model for Incompressible Navier-Stokes Equations with Partial Viscosity - Thomas Y. Hou
In this short note, we study the local well-posedness of a 3D model for incompressible Navier-Stokes equations with partial viscosity. This model was originally proposed by Hou-Lei in \cite{HouLei09a}. In a recent paper, we prove that this 3D model with partial viscosity will develop a finite time singularity for a class of initial condition using a mixed Dirichlet Robin boundary condition. The local well-posedness analysis of this initial boundary value problem is more subtle than the correspon...
Downloads: 9
[texts]Oscillation and Instabilities of Relativistic Stars - Kostas D. Kokkotas
In this short review we discuss the relevance of ongoing research into stellar oscillations and associated instabilities for the detection of gravitational waves and the future field of ``gravitational-wave astronomy''.
Downloads: 3
[texts]HST Proper Motion confirms the optical identification of the nearby pulsar PSR 1929+10 - Roberto P. Mignani
We report on the proper motion measurement of the proposed optical counterpart of the X-ray/radio pulsar PSR 1929+10. Using images obtained with the HST/STIS (average epoch 2001.73) we computed a yearly displacement of +97 +/- 1 mas yr^{-1} in RA and +46 +/- 1 mas yr^{-1} in Dec since the epoch (1994.52) of the original HST/FOC detection. Both the magnitude and direction of the optical proper motion components are found to be fully consistent with the most recent VLBA radio measurements...
[texts]Differences Between Hole and Electron Doping of a Two-Leg CuO Ladder - S. Nishimoto
Here we report results of a density-matrix-renormalization-group (DMRG) calculation of the charge, spin, and pairing properties of a two-leg CuO Hubbard ladder. The outer oxygen atoms as well as the rung and leg oxygen atoms are included along with near-neighbor and oxygen-hopping matrix elements. This system allows us to study the effects of hole and electron doping on a system which is a charge transfer insulator at a filling of one hole per Cu and exhibits power law, d-wave-like pairing corre...
[texts]Tracking Simulations Near Half-Integer Resonance at PEP-II - Y. Cai
Beam-beam simulations predict that PEP-II luminosity can be increased by operating the horizontal betatron tune near and above a half-integer resonance. However, effects of the resonance and its synchrotron sidebands significantly enhance betatron and chromatic perturbations which tend to reduce dynamic aperture. In the study, chromatic variation of horizontal tune near the resonance was minimized by optimizing local sextupoles in the Interaction Region...
[texts]Construction of wedge-local QFT through Longo-Witten endomorphisms - Yoh Tanimoto
We review our recent construction of operator-algebraic quantum field models with a weak localization property. Chiral components of two-dimensional conformal fields and certain endomorphisms of their observable algebras play a crucial role. In one case, this construction leads to a family of strictly local (Haag-Kastler) nets.
[texts]arxiv-0907.2408
[texts]arxiv-physics0211017

Downloads: 1
[texts]Power-laws and the Conservation of Information in discrete token systems: Part 2 The role of defect - Les Hatton
In a matching paper (arXiv:1207.5027), I proved that Conservation of Size and Information in a discrete token based system is overwhelmingly likely to lead to a power-law component size distribution with respect to the size of its unique alphabet. This was substantiated to a very high level of significance using some 55 million lines of source code of mixed provenance. The principle was also applied to show that average gene length should be constant in an animal kingdom where the same constrain...
[texts]Hubbard model description of silicon spin qubits: charge stability diagram and tunnel coupling in Si double quantum dots - S. Das Sarma
We apply the recently introduced Hubbard model approach to quantitatively describe the experimental charge stability diagram and tunnel coupling of silicon double quantum dot systems. The results calculated from both the generalized Hubbard model and the microscopic theory are compared with existing experimental data, and excellent agreement between theory and experiment is found. The central approximation of our theory is a reduction of the full multi-electron multi-band system to an effective ...
Downloads: 3
[texts]The incomplete beta function law for parallel tempering sampling of classical canonical systems - Cristian Predescu
We show that the acceptance probability for swaps in the parallel tempering Monte Carlo method for classical canonical systems is given by a universal function that depends on the average statistical fluctuations of the potential and on the ratio of the temperatures. The law, called the incomplete beta function law, is valid in the limit that the two temperatures involved in swaps are close to one another...
Downloads: 1
[texts]The Automorphic Membrane - Boris Pioline
We present a 1-loop toroidal membrane winding sum reproducing the conjectured $M$-theory, four-graviton, eight derivative, $R^4$ amplitude. The $U$-duality and toroidal membrane world-volume modular groups appear as a Howe dual pair in a larger, exceptional, group. A detailed analysis is carried out for $M$-theory compactified on a 3-torus, where the target-space $Sl(3,\Zint)\times Sl(2,\Zint)$ $U$-duality and $Sl(3,\Zint)$ world-volume modular groups are embedded in $E_{6(6)}(\Zint)$...
Downloads: 2
[texts]Second order chiral restoration phase transition at low temperatures in quarkyonic matter - L. Ya. Glozman
In this Addendum to our recent paper, Phys. Rev. D 77, 054027 (2008), we point out that a chiral restoration phase transition in a quarkyonic matter at low temperatures is of second order within a manifestly confining and chirally symmetric large $N_c$ model. This result is qualitatively different as compared to NJL and NJL-like models that are not confining and might have some implications for the existence or nonexistence of the critical end point in the QCD phase diagram.
Downloads: 3
[texts]Very strong and slowly varying magnetic fields as source of axions - Giorgio Calucci
The investigation on the production of particles in slowly varying but extremely intense magnetic field in extended to the case of axions. The motivation is, as for some previously considered cases, the possibility that such kind of magnetic field may exist around very compact astrophysical objects.
[texts]Revising Type-2 Computation and Degrees of Discontinuity - Martin Ziegler
By the sometimes so-called MAIN THEOREM of Recursive Analysis, every computable real function is necessarily continuous. Weihrauch and Zheng (TCS'2000), Brattka (MLQ'2005), and Ziegler (ToCS'2006) have considered different relaxed notions of computability to cover also discontinuous functions. The present work compares and unifies these approaches. This is based on the concept of the JUMP of a representation: both a TTE-counterpart to the well known recursion-theoretic jump on Kleene's Arithmeti...
Downloads: 1
[texts]2+1-Gravity and The Embedding its Dynamiycal Symmetry and Para-Supersymmetry into SO(4,c) Group - M. A. Jafarizadeh
Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with deficit of angle at the location of point mass. The quantum mechanics of a point particle in these spacetimes in the absence of angular deficit has been solved algebraically both relati...
Downloads: 3
[texts]Abundance analysis of the slow nova PW Vulpeculae 1984 - Greg J. Schwarz
We determine the elemental abundances for the ejecta of the slow nova PW Vul 1984. Our technique uses a minimization of the emission line fits of a photoionization model to available ultraviolet, optical and infrared spectra. We find the following abundances (by number) with respect to solar: He/H = 1.0 $\pm$ 0.4, C/H = 7.0 $^{+7}_{-4}$, N/H = 85 $^{+59}_{-41}$ and O/H = 6 $^{+7}_{-2}$. In addition, there is weak evidence for solar Ne and Mg and twice solar Fe...
Downloads: 4
[texts]Fermi-edge problem in the presence of AC electric field - Yi Zhou
We study in this paper a non-equilibrium Fermi-edge problem where the system under investigation is a single electron reservoir putting under an AC electric field. We show that the electron Green's function and other correlation functions in the problem can be solved and expressed exactly in terms of a well-defined integral. The qualitative behaviors of the solution is studied and compared with the situation where the impurity is coupled to more than one reservoirs at different chemical potentia...
Downloads: 3
[texts]Fitting birth-death processes to panel data with applications to bacterial DNA fingerprinting - Charles R. Doss
Continuous-time linear birth-death-immigration (BDI) processes are frequently used in ecology and epidemiology to model stochastic dynamics of the population of interest. In clinical settings, multiple birth-death processes can describe disease trajectories of individual patients, allowing for estimation of the effects of individual covariates on the birth and death rates of the process. Such estimation is usually accomplished by analyzing patient data collected at unevenly spaced time points, r...
Downloads: 1
[texts]Preliminary results of the heavy-light meson spectrum using chirally improved light quarks - Tommy Burch
Using a ``wall'' of quark point sources, we invert the chirally improved Dirac operator to create an ``incoherent'' collection of quark propagators which originate from all spatial points of the source time slice. The lowest-order NRQCD approximation is used to create heavy-quark propagators from the same wall source. However, since the numerical cost involved in computing such heavy-quark propagators is low, we are able to use a number of source gauge paths to establish coherence between the he...
Downloads: 7
[texts]Supernova neutrinos in the light of FCNC - S. W. Mansour
We study the effect of including flavor changing neutral currents (FCNC) in the analysis of the neutrino signal of a supernova burst. When we include the effect of the FCNC which are beyond the standard model (SM) in the study of the MSW resonant conversion, we obtain dramatic changes in the \Delta m^2-sin^2(2\theta) probability contours for neutrino detection.
Downloads: 1
[texts]MITRA: A Meta-Model for Information Flow in Trust and Reputation Architectures - Eugen Staab
We propose MITRA, a meta-model for the information flow in (computational) trust and reputation architectures. On an abstract level, MITRA describes the information flow as it is inherent in prominent trust and reputation models from the literature. We use MITRA to provide a structured comparison of these models. This makes it possible to get a clear overview of the complex research area. Furthermore, by doing so, we identify interesting new approaches for trust and reputation modeling that so f...
Downloads: 3
[texts]Scaling laws for Shor's algorithm with a banded quantum Fourier transform - Y. S. Nam
We investigate the performance of a streamlined version of Shor's algorithm in which the quantum Fourier transform is replaced by a banded version that for each qubit retains only coupling to its $b$ nearest neighbors. Defining the performance $P(n,b)$ of the $n$-qubit algorithm for bandwidth $b$ as the ratio of the success rates of Shor's algorithm equipped with the banded and the full bandwidth ($b=n-1$) versions of the quantum Fourier transform, our numerical simulations show that $P(n,b) \ap...
Downloads: 1
[texts]Dimensional regularization of the gravitational interaction of point masses - Thibault Damour
We show how to use dimensional regularization to determine, within the Arnowitt-Deser-Misner canonical formalism, the reduced Hamiltonian describing the dynamics of two gravitationally interacting point masses. Implementing, at the third post-Newtonian (3PN) accuracy, our procedure we find that dimensional continuation yields a finite, unambiguous (no pole part) 3PN Hamiltonian which uniquely determines the heretofore ambiguous ``static'' parameter: namely, $\omega_s=0$...
Downloads: 1
[texts]Scalar Matter Coupled to Quantum Gravity in the Causal Approach: Finite One-Loop Calculations and Perturbative Gauge Invariance - Nicola Grillo
Quantum gravity coupled to scalar massive matter fields is investigated within the framework of causal perturbation theory. One-loop calculations include matter loop graviton self-energy and matter self-energy and yield ultraviolet finite and cutoff-free expressions. Perturbative gauge invariance to second order implies the usual Slavnov-Ward identities for the graviton self-energy in the loop graph sector and generates the correct quartic graviton-matter interaction in the tree graph sector...
Downloads: 1
[texts]Equivalence-Checking on Infinite-State Systems: Techniques and Results - Antonin Kucera
The paper presents a selection of recently developed and/or used techniques for equivalence-checking on infinite-state systems, and an up-to-date overview of existing results (as of September 2004).
[texts]The microscopic meaning of grand potential: cluster properties of the one-dimensional lattice gas - Agata Fronczak
We demonstrate, with a concrete example, how the combinatorial approach to a general system of particles, which was introduced in detail in the earlier paper arXiv:1205.4986, works and where it enters to provide a genuine extension of results obtainable by more traditional methods of statistical mechanics. To this end, an effort is made to study cluster properties of the one-dimensional lattice gas with nearest neighbor interactions...
[texts]On excess filtration on the Steenrod algebra - Atsushi Yamaguchi
In this note, we study some properties of the filtration of the Steenrod algebra defined from the excess of admissible monomials. We give several conditions on a cocommutative graded Hopf algebra A^* which enable us to develop the theory of unstable A^*-modules.
Downloads: 2
[texts]Fibonacci-Hubbard Chain at Zero and Finite Temperatures - Sanjay Gupta
We have studied finite-sized single band Hubbard chains with Fibonacci modulation for half filling within a mean field approximation. The ground state properties, together with the dc conductivity both at zero and non-zero temperatures, are calculated for such quasi-periodic Hubbard chains. While a reduction in the conductivity is found for strong electronic interaction or strong Fibonacci modulation, a competition between these two is observed to enhance the conductivity...
Downloads: 1
[texts]Note on a sigma model connection with instanton dynamics - Amir H. Fariborz
It is well known that the instanton approach to QCD generates an effective term which looks like a three flavor determinant of quark bilinears. This has the right behavior to explain the unusual mass and mixing of the $\eta(958)$ meson, as is often simply illustrated with the aid of a linear SU(3) sigma model. It is less well known that the instanton analysis generates another term which has the same transformation property but does not have a simple interpretation in terms of this usual linear ...
Downloads: 2
[texts]Classical and quantum spinor cosmology with signature change - B. Vakili
We study the classical and quantum cosmology of a universe in which the matter source is a massive Dirac spinor field and consider cases where such fields are either free or self-interacting. We focus attention on the spatially flat Robertson-Walker cosmology and classify the solutions of the Einstein-Dirac system in the case of zero, negative and positive cosmological constant $\Lambda$. For $\Lambda
[texts]On Measuring Chemical Abundances in Distant Galaxies Using Global Emission Line Spectra - Henry A. Kobulnicky
The advent of 8--10 meter class telescopes enables direct measurement of the chemical properties in the ionized gas of cosmologically--distant galaxies with the same nebular analysis techniques used in local H II regions. We show that spatially unresolved (i.e., global) emission line spectra can reliably indicate the chemical properties of distant star-forming galaxies. However, standard nebular chemical abundance measurement methods (those with a measured electron temperature from [O III] lambd...
[texts]Connecting certain rigid birational non-homeomorphic Calabi--Yau threefolds via Hilbert scheme - Nam-Hoon Lee
We shall give an explicit pair of birational projective Calabi--Yau threefolds which are rigid, non-homeomorphic, but are connected by projective flat deformation over some connected base scheme.
[texts]Magnon-Mediated Pairing and Isotope Effect in Iron-based Superconductors - Jiansheng Wu
Within a minimal model for the iron-based superconductors in which itinerant electrons interact with a band of local moments, we derive a a general conclusion for multi-band superconductivity. In a multi-band superconductor, due to the Adler theorem, the inter-band scattering dominates the intra-band scattering at the long wave length limit as long as both interactions are induced by Goldstone boson (which is magnon in our case) and the transfered momentum is nonzero...
Downloads: 2
[texts]Rapidity-Separation Dependence and the Large Next-to-Leading Corrections to the BFKL Equation - Carl R. Schmidt
Recent concerns about the very large next-to-leading logarithmic (NLL) corrections to the BFKL equation are addressed by the introduction of a physical rapidity-separation parameter $\Delta$. At the leading logarithm (LL) this parameter enforces the constraint that successive emitted gluons have a minimum separation in rapidity, $y_{i+1}-y_i>\Delta$. The most significant effect is to reduce the BFKL Pomeron intercept from the standard result as $\Delta$ is increased from 0 (standard BFKL)...
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